1. Field of the Invention
The present invention relates generally to medical systems and methods. More particularly, the invention relates to delivery systems having an ultrasound probe for improved imaging and a curved needle for ablation treatment, and methods for using the same.
2. Background of the Invention
Treatment of the female reproductive tract and other conditions of dysfunctional uterine bleeding and fibroids remain with unmet clinical needs. Fibroids are benign tumors of the uterine myometria (muscle) and are the most common tumor of the female pelvis. Fibroid tumors affect up to 30% of women of childbearing age and can cause significant symptoms such as discomfort, pelvic pain, mennorhagia, pressure, anemia, compression, infertility, and miscarriage. Fibroids may be located in the myometrium (intramural), adjacent the endometrium (submucosal), or in the outer layer of the uterus (subserosal). Most common fibroids are a smooth muscle overgrowth that arise intramurally and can grow to be several centimeters in diameter.
Current treatments for fibroids include either or both pharmacological therapies and surgical interventions. Pharmacological treatments include the administration of medications such as NSAIDS, estrogen-progesterone combinations, and GnRH analogues. All medications are relatively ineffective and are palliative rather than curative.
Surgical interventions include hysterectomy (surgical removal of the uterus) and myomectomy. Surgical myomectomy, in which fibroids are removed, is an open surgical procedure requiring laparotomy and general anesthesia. Often these surgical procedures are associated with the typical surgical risks and complications along with significant blood loss and can only remove a portion of the culprit tissue.
To overcome at least some of the problems associated with open surgical procedures, laparoscopic myomectomy was pioneered in the early 1990's. However, laparoscopic myomectomy remains technically challenging, requiring laparoscopic suturing, limiting its performance to only the most skilled of laparoscopic gynecologists. Other minimally invasive treatments for uterine fibroids include hysteroscopy, uterine artery ablation, endometrial ablation, and myolysis.
While effective, hysterectomy has many undesirable side effects such as loss of fertility, open surgery, sexual dysfunction, and long recovery time. There is also significant morbidity (sepsis, hemorrhage, peritonitis, bowel and bladder injury), mortality and cost associated with hysterectomy. Hysteroscopy is the process by which a thin fiber optic camera is used to image inside the uterus and an attachment may be used to destroy tissue. Hysteroscopic resection is a surgical technique that uses a variety of devices (loops, roller balls, bipolar electrodes) to ablate or resect uterine tissue. The procedure requires the filling of the uterus with fluid for better viewing, and thus has potential side effects of fluid overload. Hysteroscopic ablation is limited by its visualization technique and thus, only appropriate for fibroids which are submucosal and/or protrude into the uterine cavity.
Uterine artery embolization was introduced in the early 1990's and is performed through a groin incision by injecting small particles into the uterine artery to selectively block the blood supply to fibroids and refract its tissue. Complications include pelvic infection, premature menopause and severe pelvic pain. In addition, long term MRI data suggests that incomplete fibroid infarction may result in regrowth of infarcted fibroid tissue and symptomatic recurrence.
Endometrial ablation is a procedure primarily used for dysfunctional (or abnormal) uterine bleeding and may be used, at times, for management of fibroids. Endometrial ablation relies on various energy sources such as cryo, microwave and radiofrequency energy. Endometrial ablation destroys the endometrial tissue lining the uterus, and although an excellent choice for treatment of dysfunctional uterine bleeding, it does not specifically treat fibroids. This technique is also not suitable treatment of women desiring future childbearing.
Myolysis was first performed in the 1980's using lasers or radio frequency (RF) energy to coagulate tissue, denature proteins, and necrose myometrium using laparoscopic visualization. Laparoscopic myolysis can be an alternative to myomectomy, as the fibroids are coagulated and then undergo coagulative necrosis resulting in a dramatic decrease in size. As with all laparoscopic techniques, myolysis treatment is limited by the fact that it can only allow for visualization of subserosal fibroids.
Needle myolysis uses a laparoscope, percutaneous, or open technique to introduce one or more needles into a fibroid tumor under direct visual control. Radio frequency current, cryo energy, or microwave energy is then delivered between two adjacent needles (bipolar), or between a single needle and a distant dispersive electrode affixed to the thigh or back of the patient (unipolar). The aim of needle myolysis is to coagulate a significant volume of the tumor, thereby cause substantial shrinkage. The traditional technique utilizes making multiple passes through different areas of the tumor using the coagulating needle to destroy many cylindrical cores of the abnormal tissue. However, the desirability of multiple passes is diminished by the risk of adhesion formation which is thought to escalate with increasing amounts of injured uterine serosa, and by the operative time and skill required. Myolysis can be an alternative to myomectomy, as the fibroids are coagulated and then undergo coagulative necrosis resulting in a dramatic decrease in size. Myolysis is generally limited by its usage with direct visualization techniques, thus being limited to the treatment of subserosal fibroids.
To overcome the limitations of current techniques, it would be desirable to provide a minimally invasive approach to visualize and selectively eradicate fibroid tumors within the uterus. The present invention addresses these and other unmet needs.